The tragic deaths of two Las Vegas police officers gunned down in a pizzeria Sunday pushed the number of US officers killed in the line of duty so far this year to 62, an increase of 38 percent since the same period of 2013.

Officers Alyn Beck and Igor Soldo were eating lunch at CiCi’s Pizza at a shopping center northeast of the Las Vegas Strip when they were shot at point-blank range. Two suspects, a man and a woman, then fled to a nearby Walmart where police say they gunned down one civilian and engaged in a firefight with law enforcement officers before the woman turned the gun on her accomplice and then herself.

Las Vegas police spokesman Larry Hadfield told the Associated Press that the motive for the rampage is still under investigation.

These are the first fatal shootings of Las Vegas police officers in the line of duty since 2006, when Sgt. Henry Prendes was ambushed during a domestic violence call.

Nationally, the rate of officer fatalities has ebbed and flowed over the years, according to the National Law Enforcement Officers Memorial Fund, which tracks the number of officers killed in the line of duty. Until this year, the number of officers killed in the line of duty had declined for two years from 171 in 2011 to 122 in 2012 to 100 in 2013.

If 2014 continues at the current rate, there could be as many as 140 on-duty fatalities, a considerable increase over the previous year, but still below the average of 150 deaths seen during the past decade. Over the longer term, the number of police officers killed in action has fallen dramatically since the 1970s, when totals consistently soared into the 200s.

Both Officers Beck and Soldo were husbands and fathers. Beck is survived by a wife and three children and Soldo leaves behind a wife and baby.

“It’s a tragic day,” Nevada's Clark County Sheriff Doug Gillespie said at a news conference Sunday, the AP reports. “But we still have a community to police and we still have a community to protect. We will be out there doing it with our heads held high, but with an emptiness in our hearts.”